1. Field of the Invention
The present invention relates to a light source apparatus and a fabrication method thereof, and more particularly, to a light source apparatus and a fabrication method thereof enabling light emitted from respective light emitting devices to be collected toward the front of a metal stem without loss of light.
2. Description of the Background Art
A light emitting device which is actively being used at the moment is typically divided into a laser diode (LD) and a light emitting diode (LED).
The LD is widely used as a light source in the field of optical communication, and has lately been used as an important component in the field of optical media such as a DVD player, a laser disc (LD) player, a mini disc (MD) player, or the like as well as in the filed of a compact disc (CD) player and a compact disc rewritable (CD-RW) player.
In addition, the LED is widely used in a backlight unit (BLU), and is used as a light source apparatus which is located at a lower portion of an LC PANEL which cannot emit by itself and makes an LCD recognized by irradiating uniform plane light.
Advantageously, the LED can be operated at a relatively low voltage, generates less heat because of high energy efficiency and has a long life span.
FIG. 1 is a longitudinal sectional view showing the conventional light emitting device, and FIG. 2 is a longitudinal sectional view showing the conventional light source apparatus.
As shown in FIG. 1, the conventional light emitting device 10 is constructed in such a manner that a buffer layer 12, an n-contact layer 13, an active layer 14 and a p-contact layer 15 are sequentially deposited over a sapphire, n-GaAs or other substrate 11 by a chemical vapor deposition (CVD) method.
A current spraying layer 16 is formed on an upper surface of the p-contact layer 15. A p-electrode 17 which is electrically connected to the p-contact layer 15 and the current spraying layer 16 is formed on an upper surface of the current spraying layer 16. Next, an n-electrode 18 is formed on an upper surface of an exposed portion of the n-contact layer 13.
As shown in FIG. 2, in the conventional light source apparatus 40, the light emitting device 10 is bonded to a sub-mount 20 by a normal mounting bonding method, and the sub-mount 20 is bonded to a metal stem 30. At this time, the p-electrode 17 of the light emitting device 10 is connected to an electrode 21 of the sub-mount 20 by a wire 11 in order to apply the external power, and the electrode 21 of the sub-mount 20 is connected to an electrode 31 of the metal stem 30 by another wire 22. Since the n-electrode 18 has the same connection structure as the p-electrode, reference numerals concerning the connection structure of the n-electrode 18 and a description therefor will be omitted hereinafter.
An operation of the conventional light source apparatus having such a construction will be described as follows.
As shown in FIGS. 1 and 2, when a voltage is applied to the electrode 31 of the metal stem 30, the voltage is applied to the p-electrode 17 and the n-electrode 18 through wires 11 and 22.
At this time, holes and electrons are injected into the p-electrode 17 and the n-electrode 18, respectively. The injected holes and electrons are introduced into the p-contact layer 15 and the n-contact layer 13 and then are recombined in the active layer 14. At this time, extra energy is changed into light, which is emitted.
However, in case of the conventional light source apparatus, light interference between the light emitting devices adjacent to each other occurs, and light emitted from the side of the light emitting device is not collected toward the front of the metal stem but disperses, thereby decreasing the luminous efficiency.
In addition, as for a connection between the light emitting device and the sub-mount and a connection between the sub-mount and the metal stem, a connection job is very difficult because the normal mounting bonding method using wires is used and thus yield is decreased.